Most of my patients with kidney stones often tell me about online advisories on how a lemonade can dissolve them. And they even tell me how it is rich in citric acid that does the good work of eroding the stones. But this is not the whole truth.
Citrus beverages usually increase citrate levels in urine, which can halt stone formation by attaching themselves to unabsorbed oxalate, the crystal-forming substance that comes into the kidney from the bloodstream for filtering. This stalls crystal formation and we know many crystals clump together to form stones. But there’s no scientific evidence to prove that citric acid, which produces citrate, can break down a calcium stone, which is what most stone patients produce. A well-formed stone will have to be treated medically.
We all know that citrus juices are high in Vitamin C, which is an antioxidant, while potassium and magnesium are stone inhibitors. So a daily recommended allowance is good enough to prevent stone formation. Besides, each kidney stone is different. Some are formed by calcium, struvite, uric acid and cystine. Struvite stones are caused by an upper urinary tract bacterial infection (UTI), which produces ammonia and makes the urine less acidic. These grow big easily. Cystine is an amino acid, excess volumes of which in the urine can cause stones.
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Regardless of the type of stone you have, the idea is to flush out substances that are malabsorbed by the body and land in the kidney for clean-up. Research shows that how much you drink to flush them out has a much greater impact than what you drink. You need to dilute the concentration of stone-forming salts and for that maintain hydration by drinking three litres every day. If you are in an air-conditioned environment, then two-and-a-half litres will do. But if you are in a more physical, outdoor environment that requires you to sweat, you have to drink more than three litres of liquids.
So how do you keep your kidneys flushed? Just look at the urine colour. Dark means your urine output should be one-and-a-half litres every day, which means washroom visits of at least five to six times. Check your urinary pH factor. An alkaline pH fuels the crystallisation of calcium- and phosphate-containing stones, an acidic urine pH causes uric acid or cystine stones.
Apart from dehydration, other factors make you prone to kidney stones. These include diabetes, obesity, family history, having a diet that’s high in protein, sodium (salt) and sugar. Excess salt increases the amount of calcium your kidneys must filter and significantly increases your risk of kidney stones. Reduce foods rich in oxalate like chocolates, soda-based drinks, cauliflowers and spinach. In fact, depending on the type of stone, we customise diets for our patients. We do a blood test and urinary analysis, take care of the mineral markers, and depending on deficiencies and excess, supplement them or find ways to cut them down. Small stones of 3mm and 4 mm can pass out through the urethra with medication. Surgical intervention is required only for bigger stones.
